Sod harvester

ABSTRACT

An improved method of mounting the cutting head of a sod harvester with respect to the conveyor employs a single ball joint between the cutting head and the conveyor, and a pair of side links spaced outwardly of the conveyor and arranged to constrain the cutting head against lateral displacement with respect to the conveyor. Preferably, the links are adjustable in length to permit vertical and lateral adjustment of the cutting head with respect to the conveyor, e.g. “tracking” of the cutting head.

FIELD OF THE INVENTION

[0001] This invention relates generally to sod harvesters.

BACKGROUND OF THE INVENTION

[0002] Sod harvesters have been commercially available for a long time,and usually are designed as self-propelled machines or as a cutting unitwhich can be attached to a conventional tractor. In either case, theharvester has a cutting head which includes (a) a generally-horizontalknife to undercut the sod at a specified depth, (b) side cutting bladesor coulters to cut the edges of the sod strip, and (c) a roller tosupport the weight of the cutting head and to establish the thickness ofthe sod strip. Cut strips of sod are delivered onto a conveyor whichconveys the strips rearwardly and upwardly away from the cutting head,for collection.

[0003] Sod harvesters have used a variety of methods to follow thecontour of the ground; in general, the objective is to allow theoperator to cut a thin strip of sod without the risk of scalping, orcutting too thinly on occasion. Some harvesters, commonly referred to as“conventional” or “fixed head” harvesters, have the cutting head rigidlyconnected to the conveyor frame. Examples of this type of harvester arethe harvester described in U.S. Pat. No. 3,540,535, the Brouwer model1555, and the Kesmac model 2100. These harvesters include a pivoting“ball joint” connection at the rear of the conveyor, which allows thecutting head to rise and fall with undulations in the direction ofmotion of the harvester. A “track rod” connects the cutting head orconveyor to the tractor with pivoting ball joints and holds the cuttinghead parallel to the direction of motion. These pivot joints also allowthe conveyor and cutting head frame to rock from side to side to followundulations perpendicular to the direction of motion of the harvester.The axis about which the conveyor and cutter assembly rotates is definedby the location of the centres of the rear pivot point and the track rodconnection to the cutting head or conveyor. Since this axis is nothorizontal, the cutting knives turn away from being exactlyperpendicular to the direction of travel when the head pivots, resultingin damage to the edges of the sod strip.

[0004] This problem is addressed by harvesters that are commonlyreferred to as “floating head”, or “pivoting head”, harvesters, whichhave a pivoting connection between the cutting head frame and theconveyor frame. U.S. Pat. Nos. 4,621,696, 3,807,504, and 4,892,152disclose harvesters of this type, in which the cutting head can tiltabout a horizontal pivot axis. The cutting knives and roller no longerpivot front-to-back. However, since the axis of tilt lies at somedistance above ground level, the cutting head can be induced to pivot bya side load on the knives and roller, such as would happen if sod isbeing cut on a curve, as is common with center-pivot irrigation sodcultivation. This can result in scalping.

[0005] One attempt to solve the floating head problem is disclosed inU.S. Pat. No. 6,112,825. This patent describes a floating head design inwhich the pivoting connection between the cutting head and the conveyoris angled, such that the pivot axis intersects the knife. It should benoted, however, that a side load on the knives and roller can induce thewhole assembly to pivot on an axis defined by the front and rear supportball joints, causing scalping.

SUMMARY OF THE INVENTION

[0006] An object of the present invention is to provide improvementsintended to address the problems of prior art sod harvesters. Inparticular, the invention provides an improved manner of mounting thecutting head to the conveyor to control uniformity in the thickness ofsod strips being harvested.

[0007] The sod harvester of the invention includes a drive unit formoving the harvester in a forward direction, a cutting head for cuttinga strip of sod from the ground as the harvester moves in said forwarddirection, and conveyor means disposed rearwardly of the cutting headfor receiving cut strips of sod from the cutting head and conveying thestrips rearwardly for collection. The invention provides means forconnecting the conveyor and the cutting head, comprising a ball jointdisposed on a longitudinal centre line of the cutting head and a pair oflaterally spaced links, each connected at one end to the conveyor meansand at the opposite end to the cutting head at respective connectionpoints that are selected to constrain the cutting head laterally withrespect to the conveyor means, while permitting lateral tilting of thecutting head about the ball joint to accommodate lateral unevenness inthe ground.

[0008] In other words, the invention provides an improved means ofconnecting the cutting head and the conveyor to allow free flotation ofthe ground-following roller and cutting knives, with substantiallyreduced scalping and damage to edges of the sod strip.

[0009] Preferably, the conveyor is pivotally mounted so that its leadingend can move up and down to follow ground contours, but is constrainedfrom side to side movement, as in most floating head harvesters. Theball joint is located below the conveyor and behind the cutting head,and the two links are to the outside of the conveyor, located at adistance vertically from the ball joint. The links constrain the cuttinghead to remain perpendicular to the direction of travel, while at thesame time allowing it to rock from side to side in response to changesin ground contour.

[0010] This mounting arrangement does not create a discrete axis aboutwhich the cutting heat pivots in relation to the conveyor frame. Anotional pivot axis can be defined as an axis that intersects the centerball joint, is oriented in the direction of travel, and is angleddownward at the same angle as the two links in their centre positions(cutting head horizontal). The actual rocking of the cutting head willdeviate from this notional axis to the extent that the ends of the linksconnected to the cutting head frame deviate from a plane normal to thenotional axis as the cutting head rocks. With the notional axis orientedto approximately the bottom of the ground-following roller,substantially less “induced pivoting” is experienced relative to priorfloating heads.

[0011] An advantage of the preferred embodiment of the invention over asingle pivot shaft between the cutting head frame and the conveyor frameis that it permits greater ground clearance.

[0012] A further advantage is that adjustable links provide a means ofadjusting the vertical distance between the back of a “sod guide” thatis usually provided at the rear of the cutting head to the leading endof the conveyor. As the links are shortened, the sod guide moves uprelative to the conveyor. This relationship is important to the smoothand gentle transfer of sod from the cutting blade to the conveyor. Priorart sod harvesters have no way of adjusting that relationship withoutchanging the depth of cut.

BRIEF DESCRIPTION OF DRAWINGS

[0013] In order that the invention may be more clearly understood,reference will now be made to the accompanying drawings which illustratea particular preferred embodiments of the invention by way of example,in contrast with the prior art.

[0014] In the drawings:

[0015]FIG. 1 is a schematic side elevational view of one form of priorart sod harvester;

[0016]FIG. 1a is an end elevational view in the direction of arrow A inFIG. 1;

[0017]FIG. 2 is a view similar to FIG. 1 illustrating a second form ofprior art sod harvester;

[0018]FIG. 2b is a view generally in the direction of B in FIG. 2;

[0019]FIG. 3 is a view similar to FIGS. 1 and 2 illustrating a thirdform of prior art sod harvester;

[0020]FIG. 3a is an enlarged view of the gage roller of FIG. 3;

[0021]FIG. 3b is a plan view of the gage roller in FIG. 3;

[0022]FIG. 4 is a side elevational view similar to FIGS. 1, 2 and 3 butillustrating a sod harvester in accordance with a preferred embodimentof the present invention;

[0023]FIG. 5 is an elevational view in the direction of arrow D in FIG.4;

[0024]FIG. 6 is a plan view of the gage roller in FIG. 4;

[0025]FIGS. 7 and 8 are plan and front elevational views correspondingto FIG. 4;

[0026]FIG. 9 is a view similar to FIG. 8 showing the cutting head of theharvester in a tilted position; and,

[0027]FIG. 10 is a perspective view of a practical example of the sodharvester as seen from the right and above in FIG. 4.

[0028] All of the views show a sod harvester in the form of a cuttingunit which is designed to be attached to a conventional tractor. Thetractor itself is not shown in detail but typically is disposed to theleft of the cutting unit in the direction of travel of the harvester, asindicated in ghost outline at T in FIG. 7. The tractor itself and themanner in which the cutting unit is coupled to the tractor are not partof the present invention. Reference may be made to the prior patentscited herein to illustrate mounting of the cutting unit to a tractor.The disclosures of those patents are incorporated herein by reference.

DESCRIPTION OF THE PRIOR ART

[0029] FIGS. 1 to 3 show three types of prior art sod harvesters whichare compared with the present invention. For the purpose of comparison,all of the harvesters are assumed to have a gage roller which is an 8″in diameter by 16″ wide and which tilts up 0.50 inches on the outsideedge. While the actual dimension of displacement sideways will vary withgeometry, using a consistent assumption will illustrate the differentresults inherent in the designs.

[0030]FIG. 1 illustrates a fixed head harvester, known commercially asthe Brouwer 1555, Brouwer 1550, Brouwer 1500, Brouwer A3A, Texasconventional, among others. The axis of rotation is defined by the rearand front support ball joints, and it falls significantly above the gageroller, in this case 13 inches. From FIG. 1a, it can be seen that a 0.50inch vertical rise requires a 0.76 inch horizontal displacement.

[0031]FIG. 2 illustrates a common fixed head design, the Brouwer 1560.The characteristic of an independent cutting head with a horizontalpivot axis relatively low to the ground is also found in U.S. Pat. Nos.4,621,696 and 4,892,152. In this case, the horizontal displacementaround the axis of rotation to accommodate a 0.50 inch rise is reducedto 0.23 inches (FIG. 2a).

[0032]FIG. 3 illustrates a fixed head design known as the Kesmac 2100.In this design, the cutter head is rigidly attached to the conveyor, asin FIG. 1, but the axis of rotation is arranged to intersect the groundclose to the gage roller, which eliminates the side shift problem ofFIGS. 1 and 2. However, since the pivot axis is at a significant anglerelative to horizontal (conservatively assumed to be 30 degrees), the0.50 inch rise causes the end of the roller to move forward 0.29 inches.As seen FIG. 3b , this results in the roller wobbling off square by 0.14inches.

DESCRIPTION OF PREFERRED EMBODIMENT

[0033] Reference will now be made to FIGS. 4 to 10 in describingparticular preferred embodiments of the invention by way of example. Forpurposes of comparison with the prior art, FIG. 4 is a schematic sideelevational view similar to FIGS. 1 to 3. Later views such as FIGS. 7 to10, provide more detail; FIGS. 9 and 10 in particular illustrate apractical form of sod harvester in accordance with the invention.

[0034] Referring initially to FIG. 4, the sod harvester of the inventionis generally indicated by reference numeral 20 and is designed to bemounted alongside a drive unit such as a tractor (“T” in FIG. 7) formovement in a forward direction indicated by arrow 22. The harvesterincludes a cutting head 24 for cutting a strip of sod as the harvestermoves in the forward direction 22, and conveyor means generallyindicated at 26 disposed rearwardly of the cutting head for receivingcut strips of sod from the cutting head and conveying the stripsrearwardly and upwardly for collection. The cutting head 24 and theconveyor means 26 may be of known design and therefore are notillustrated in detail. The invention resides in the provision of meansfor connecting the conveyor and the cutting head, as will be described.For present purposes, it is sufficient to note that the cutting head 24includes a cutting head frame 28, and a gage roller 30 which is mountedbelow the frame 28. Roller 30 partially supports the weight of thecutting head and follows the contour of the ground as the harvestermoves in the direction of travel 22. FIG. 4 does not show theundercutting knife or the side blades that are typically provided inassociation with the gage roller 30, since these components and theirrelationship with the gage roller are conventional.

[0035] The conveyor means 26 includes a conveyor frame 32 whichessentially comprises a pair of side frame members 34 (FIG. 10) betweenwhich a conveyor belt is supported for conveying cut strips of sodupwardly and rearwardly away from the cutting head. In FIG. 10, the beltitself is not shown but reference numeral 36 indicates sprockets aroundwhich the belt travels. A pair of brackets 38 project upwardly from theconveyor side frame members 34 and define a transverse pivot axis 40(see FIG. 4) at which the conveyor frame is coupled to the drive unit sothat the conveyor can pivot up and down to follow ground contours.Side-to-side tilting motion of the conveyor frame is not provided for.

[0036] In accordance with the present invention, connecting means areprovided between the conveyor frame 32 and the cutting head frame 28,and comprise a spherical ball joint 42 that is disposed on alongitudinal centre line of the cutting head (denoted 44 in FIG. 7), anda pair of laterally spaced links 46, 48 disposed outwardly of therespective frames 28 and 32 (see FIG. 7). Each of the links 46, 48 isconnected at one end to the conveyor frame and at its opposite end tothe cutting head frame. The two connection points for link 46 aredenoted 50 and 52, and the corresponding connection points for link 48are denoted 54 and 56. The connection points are selected to constrainthe cutting head 24 laterally with respect to the conveyor means whilepermitting lateral tilting of the cutting head about the ball joint 42to accommodate lateral unevenness in the ground.

[0037]FIG. 4 shows the relationship between the ball joint 42, the link46 and its pivot points 50 and 52. When the cutting head 24 is on ahorizontal surface, the corresponding link 48 and connection points 54and 56 at the opposite side of the harvester are in the same position aslink 46 and its connection points 50 and 52. Each of the connectionpoints 50, 52, 54 and 56 is provided by a ball joint.

[0038] The centre-line ball joint 42 constrains all points on thecutting head to remain at a Constance distance from the ball joint. Thetwo links 46 and 48 connect the conveyor frame 32 to the cutting headframe 28 at a distance vertically from ball joint 42. These links holdthe cutting head frame 28 in the desired position relative to theconveyor means 26 and the direction of travel 22.

[0039] The rocking action of the head 24 and the optimal orientation ofthe links 46, 48 can be best understood by imagining a notional pivotaxis 58 located by the center of ball joint 42 and the center of thecontact line between the gage roller 30 and the ground. A co-ordinatesystem can be assigned with the z direction pointing down that notionalaxis 58, with the y direction normal to z on a vertical plane, and the xdirection horizontal, normal to z, as shown in FIGS. 4 and 5. In orderfor the cutting head frame to actually pivot about the notional axis,ball joints 52 and 56 would need to travel on the circle formed by theintersection of a plane P normal to the z direction with a spherecentered on ball joint 42 with radius equal to the distance from balljoint 42 to ball joints 52 and 56. This circle is shown on FIG. 5, with52′ and 56′ being the ball joints 52 and 56 in the rotated position.Since the ball joints 52 and 56 are at the end of links 46 and 48, theyare constrained to maintain a constant distance from ball joints 50 and54, and therefore will leave that plane P as the head rocks, by somedistance in the negative z direction. However, it will be appreciatedthat the closest approximation to the condition of the cutting headrotating about the notional axis would exist if the links 46 and 48 wereperpendicular to the plane P when the cutting head is in the horizontalposition. In that case, the negative z distance by which ball joints 52and 56 leave plane P is minimized. Also, links 46 and 48 should be aslong as practical, in order to minimize the deviation from plane P.

[0040] Links 46 and 48 being perpendicular to plane P is also importantbecause that causes the distance by which the ball joint leaves plane Pto be the same for ball joint 52 as for ball joint 56. If one pointmoved further in the negative z direction than the other, the cuttinghead would experience rotation about the y axis, which is undesirablebecause the cutting head would no longer be parallel to the direction oftravel.

[0041] In order to compare this design with prior art, analysis of sideshift and wobble was done with a CAD model rather than simplecalculations, since there is no pivoting about an axis. For the same0.50 rise on one side of the roller, horizontal displacement was 0.09inches, and the wobble off square was 0.051 inches, as shown in FIG. 6.This wobble, or “yaw” can be explained by the fact that the notionalaxis is not exactly horizontal.

[0042] In summary, the motion of the cutting head 24 includes a minor“yaw” component that is significantly less than what has been calculatedfor prior art designs. Additionally, as can most clearly be seen fromFIG. 4, ground clearance behind the cutter head is substantiallyimproved as compared with prior art arrangements in which a pivot shaftis provided in the area to the left of the ball joint 42 along axis 58.That whole area can now remain unobstructed.

[0043] In any of the inventive embodiments, the side links 46 and 48preferably are adjustable in length so as to permit adjustment oftracking of the cutting head 24 relative to the conveyor frame 32. Thelinks can also be adjusted to vary the vertical distance between the sodguide (not shown) that is typically provided on the cutting head 24, andthe conveyor 32 to assure smooth and gentle transfer of sod from thecutting head to the conveyor.

[0044] As noted previously, FIG. 10 shows a practical example of a sodharvester in accordance with the preferred embodiment of the invention.FIG. 10 will not be described in detail since the principal componentsare well known and not part of the invention. The invention resides inthe connecting means between the conveyor frame 32 and the cutting headframe 28, namely the ball joint 42 and the links 46 and 48. Thosecomponents have been indicated in FIG. 10, as has the gage roller 30 andan associated cutter blade assembly, which is generally denoted 60.Precise constructional details of the cutting head frame and theconveyor frame will not be described and may vary. A connection pointfor a track rod connection to the tractor is provided at the oppositeside of the cutting head frame 28 from that seen in FIG. 10 in aposition corresponding to the point that is denoted 62.

[0045] Each of the links 46, 48 has an end fitting that isscrew-threaded into the main body of the link so that the length of thelink can be adjusted. In FIG. 10, the main body of link 46 is denoted 46a and the screw-in end fitting is denoted 46 b. In this embodiment, thelink would of course have to be disconnected from the frame in order toeffect adjustment. Fitting 46 b would be screwed into or out of the mainbody 46 a and then the link re-connected. The construction of link 48 isessentially the same.

[0046] It will of course be appreciated that the preceding descriptionrelates to a particular preferred embodiment of the invention and thatmany modifications are possible within the broad scope of the invention.Some of those modifications have been indicated previously and otherswill be apparent to a person skilled in the art.

[0047] In particular, it is to be understood that the sod harvester ofthe invention may be powered other than by a tractor; the harvester maybe self-propelled, i.e. have a built-in drive unit.

1. A sod harvester comprising a drive unit for moving the harvester in aforward direction; a cutting head for cutting a strip of sod from theground as the harvester moves in said forward direction; conveyor meansdisposed rearwardly of the cutting head for receiving cut strips of sodfrom the cutting head and conveying the strips rearwardly forcollection; and means connecting the conveyor and the cutting head,comprising a ball joint disposed on a longitudinal centre line of thecutting head and a pair of laterally spaced links, each connected at oneend to the conveyor means and at an opposite end to the cutting head atrespective connection points that are selected to constrain the cuttinghead laterally with respect to the conveyor means while permittinglateral tilting of the cutting head about the ball joint to accommodatelateral unevenness in the ground.
 2. A sod harvester as claimed in claim1, wherein the cutter head includes a gage roller that makes linecontact with a ground surface over which the sod harvester moves,wherein each of the said pair of laterally spaced links is disposedapproximately parallel to a line connecting the centre of the ball jointand the centre of a line of contact between the surface of the rollerand the ground.
 3. A sod harvester as claimed in claim 1, wherein eachof said links is adjustable in length to permit lateral and verticaladjustment of the cutting head with respect to the conveyor means.
 4. Asod harvester as claimed in claim 1, wherein the cutting head includes acutting head frame and the conveyor means includes a conveyor frame, andwherein the said pair of links connect the two frames and are disposedlaterally outwardly of said conveyor frame.
 5. A sod harvester asclaimed in claim 4, wherein each said link in said pair of links isprovided at each end with a ball joint by which the link is connected tothe respective cutting head frame and conveyor frame.
 6. In a sodharvester that includes a cutting head for cutting a strip of sod fromthe ground as the harvester moves in a forward direction, and conveyormeans disposed rearwardly of the cutting head for receiving cut stripsof sod from the cutting head and conveying the strips rearwardly forcollection; the improvement comprising: a ball joint disposed on alongitudinal centre-line of the cutting head and connecting the cuttinghead and conveyor means, and a pair of laterally spaced links, eachconnected at one end to the conveyor means and at an opposite end to thecutting head at respective connection points that are selected toconstrain the cutting head laterally with respect to the conveyor meanswhile permitting lateral tilting of the cutting head about the balljoint to accommodate lateral unevenness in the ground.
 7. A sodharvester comprising: a cutting head; a conveyor device; a ball jointcoupling said cutting head and said conveyor device along a longitudinalaxis; and a pair of laterally spaced links each interconnecting saidcutting head and said conveyor device, said ball joint and said pair oflaterally spaced links cooperating to maintain axial alignment of saidcutting head and said conveyor device along said longitudinal axis whilesimultaneously permitting tilting movement of said cutting head relativeto said conveyor device about said longitudinal axis.
 8. The sodharvester according to claim 7, further comprising: a gage rolleroperably coupled to said cutting head, said gage roller maintaining apredetermined cutting height of said cutting head relative to a groundsurface.
 9. The sod harvester according to claim 8 wherein said pair oflaterally spaced links are positioned generally parallel to a lineconnecting said ball joint with a line of contact between said gageroller and said ground surface.
 10. The sod harvester according to claim7 wherein each of said pair of laterally spaced links is adjustable topermit adjustment of said cutting head relative to said conveyor device.11. The sod harvester according to claim 7 wherein each of said pair oflaterally spaced links is rotatably interconnecting said cutting headand said conveyor device.
 12. A sod harvester comprising: a cuttinghead; a conveyor device; and a coupling device coupling said cuttinghead and said conveyor device, said coupling device operable to maintainaxial alignment of said cutting head and said conveyor device along alongitudinal axis while simultaneously permitting tilting movement ofsaid cutting head relative to said conveyor device about saidlongitudinal axis.
 13. The sod harvester according to claim 12 whereinsaid coupling device comprises: a ball joint coupling said cutting headand said conveyor device along said longitudinal axis; and a pair oflaterally spaced links each interconnecting said cutting head and saidconveyor device, said ball joint and said pair of laterally spaced linkscooperating to maintain axial alignment of said cutting head and saidconveyor device along said longitudinal axis while simultaneouslypermitting tilting movement of said cutting head relative to saidconveyor device about said longitudinal axis.
 14. The sod harvesteraccording to claim 13, further comprising: a gage roller operablycoupled to said cutting head, said gage roller maintaining apredetermined cutting height of said cutting head relative to a groundsurface.
 15. The sod harvester according to claim 14 wherein said pairof laterally spaced links are positioned generally parallel to a lineconnecting said ball joint with a line of contact between said gageroller and said ground surface.
 16. The sod harvester according to claim12 wherein each of said pair of laterally spaced links is adjustable topermit adjustment of said cutting head relative to said conveyor device.17. The sod harvester according to claim 12 wherein each of said pair oflaterally spaced links is rotatably interconnecting said cutting headand said conveyor device.